Doctors thought I was pregnant despite my husband's vasectomy - it turned out to be one of the rarest female cancers ever

A mother-of-three has warned how her rare uterine cancer was mistaken for a pregnancy, despite her husband's vasectomy months prior. 

In 2009, 23-year-old Courtney Snalium of Texas was waiting at an urgent care for a case of bronchitis when she fainted. 

Despite the fact her husband had just had a vasectomy the year before, doctors insisted on ordering a pregnancy test as they said it was standard procedure in the hospital. Surprisingly, it came back positive. 

However, Ms Snalium's HCG (human chorionic gonadotropin) levels, which are produced by the placenta during pregnancy to thicken the uterine wall, were low for a pregnant woman - about 20 times lower than what they should have been. 

While she and doctors were left confused for months, the theology student finally went for additional testing and was eventually diagnosed with placental site trophoblastic tumor (PSTT), a disease so rare just 300 cases have ever been recorded in medical literature.

Courtney Snalium was 23 when doctors mistook her extremely rare cancer - placental site trophoblastic tumor (PSTT) - for pregnancy

Following her positive pregnancy test, doctors suggested Ms Snalium, now 39, get additional bloodwork to make sure her HCG levels were increasing normally, but she decided against it. 

'I had already had three flawless pregnancies and I figured this one is probably fine too,' Ms Snalium said in a TikTok video.  

However, an OB/GYN urged her to get more testing and a week later, Ms Snalium's HCG was 12 - unchanged from her first test - despite the fact it normally doubles every other day during pregnancy.

'The doctor says, "I've asked my colleagues. None of us know what this could be, but one thing we are confident in is that you do not in fact have a viable pregnancy," she said. 

'We scheduled an ultrasound, and nothing showed up on the ultrasound.' 

Thinking the pregnancy was not viable, doctors performed a dilation and curettage (D&C), a procedure that removes tissue from the uterus. It can be used in cases of a miscarriage or to terminate a pregnancy within the first trimester.  

Three months after her positive pregnancy test, results from her D&C led Ms Snalium to finally be diagnosed with placental site trophoblastic tumor (PSTT), which forms from leftover cells that attach the placenta to the uterine wall during pregnancy.

Because the leftover cells form from placenta, small amounts of the pregnancy hormone HCG are released, which appear as a positive pregnancy test. 

Despite her positive pregnancy test, the levels of the pregnancy hormone HCG failed to rise normally, Ms Snalium said. Her levels were 20 times lower than they should have been

Doctors were able to treat her cancer by performing a hysterectomy, in which the uterus and often the cervix are removed. About 15 years later, Ms Snalium is cancer free

She said: 'I had one of the rarest female cancers that exists.'

'What makes these tumors kind of unique is that they don't respond to chemotherapy. Most cancers [are] rapidly dividing cells, and chemotherapy attacks rapidly dividing cells.

'But this one is very slow growing, so the prognosis completely depends on when they catch it.' 

If PSTT is caught before it spreads, it can be successfully cured with a hysterectomy, a surgery that removes a woman's uterus and cervix. 

However, if the cancer spreads - this form typically goes to the lungs - 'the prognosis is very grim,' Ms Snalium said. 

Experts estimate the cancer spreads in about 30 percent of cases and tumors can be found anywhere from one to 14 years after pregnancy. 

The cancer can also spread to the liver, lymph nodes, and brain. 

There is no confirmed survival rate for the cancer since it is so rare, but doctors estimate it can range from 30 percent if it has spread throughout the body to up to 90 percent if it has remained localized.  

Doctors estimated Ms Snalium's tumor had been growing for about 18 months, and in another six months, it likely would have spread. 

'I had no symptoms,' she said. 'A little breakthrough spotting [vaginal bleeding], but nothing that would have ever been a cause for concern.'

Typical symptoms of PSTT include abnormal vaginal bleeding or amenorrhea, the loss of periods.  

'It was a whoopsy daisy discovery that only happened because I had a case of bronchitis that was so bad that it made me faint. It was totally unrelated,' Ms Snalium added.

Doctors performed a hysterectomy and check Ms Snalium's blood regularly for rising HCG levels or other abnormalities. 

Fifteen years later, she is still cancer free, adding : 'I love to tease my husband about how he had his vasectomy for nothing.'